Clinical examination procedure for medical diagnosis includes a biochemical analysis and an immunological analysis for protein, sugar, lipid, enzymes, hormones, inorganic ions, disease markers in a biological sample such as blood and urine. Such clinical examination requires processing of a plurality of items to be examined reliably and quickly, and so a large part of the examination is executed by an automatic analysis device.
Reactions to be measured by an automatic analysis device mainly include two types of reactions that are color reactions between a substrate and an enzyme and immune reactions between an antigen and an antibody. An analysis based on the former reaction is called a biochemical analysis, and examines items such as LDH, ALP and AST. The biochemical analysis is to analyze, as an analysis target, a reaction liquid that is prepared by mixing a desired reagent with a sample such as serum, and to measure its absorbance. An analysis based on the latter reaction is called an immunity analysis, and examines items such as CRP, IgG and RF. Some substances to be measured in the latter case have an item to be examined, which requires quantification at a low-concentration area of a low blood level, and such an item is examined by a latex immunity analysis using, as a sensitizer, latex particles having a surface sensitized (bound) to an antibody.
Patent Literature 1 describes an automatic analysis device to measure the turbidity or the like of a liquid sample based on a change in diffused light, and the automatic analysis device described includes a light-shielding rotary cover with a dispensing hole so as to cover a reaction-container holding disk. After dispensing a reagent into a reaction container through the dispensing hole at the light-shielding rotary cover, and then rotating the light-shielding rotary cover until the dispensing hole is rotated from the above a photometer to the opposite side, measurement is performed while keeping the photometer in a dark-room state.